1. Field of the Invention
The present invention relates to improvements in plasma display panels and to improvements in methods of driving plasma display panels. In particular, the present invention provides a plasma display panel (referred to hereinafter as “PDP”) with an optimal cell structure such as a thickened portion of dielectric layer for each cell, and an improved driving structure for optimally driving a PDP.
2. Related Art
A cathode ray tube (CRT) has long been the display device for displaying images on a television. In a CRT display, a gun fires a beam of negatively-charged particles (electrons) inside a large glass tube. The electrons excite phosphor atoms along the wide end of the tube, which causes the phosphor atoms to light up. The video image is produced by lighting up different areas of the phosphor coating with different colors at different intensities. Although the CRT has long been used to display video images, it is bulky. In other words, in order to increase the screen width in a CRT display, the length of the tube must be increased as well in order to give the scanning electron gun room to reach all parts of the screen. Consequently, a CRT having a big screen is heavy and takes up a sizeable space.
The conventional PDP was introduced to overcome some of the drawbacks of the CRT display. Specifically, the conventional PDP provides a display device with a large display screen in the form of a flat panel display, and provides an image quality and performance equal to or superior to the CRT display.
What is desired in a PDP is a bright and clear image with a low consumption of power. Conventionally, this has not been easy to achieve, since the basic process of producing visible light by UV excitation of phosphor is rather marginal.
Alternating current (AC) PDPs have basically two types of discharge methods. The first type involves production of a surface discharge between coplanar electrodes. This requires a three-electrode structure, which is known to be stable and is quite popular. The second type involves production of a discharge between noncoplanar electrodes, or electrodes that are on opposite sides of the cell. This is a two-electrode structure and has a lower discharge voltage and higher efficiency. However, the two-electrode structure has a number of practical drawbacks, and has not come into common use as yet. Hence, improvement of the brightness and reduction of the power consumption have been, and remain important objectives of the three-electrode type of PDP. That is, the main design objective of this type of PDP is to improve the discharge efficiency, i.e. to increase the strength of luminescence per unit of injected energy.
FIG. 1 illustrates a top view of a conventional PDP 10. PDP 10 is a matrix device having a basic grid of individual cells 12, which are defined by closed shaped barrier ribs 14. Typically, each cell is dedicated to producing visible light in either the red, green or blue wavelengths, with a group of red, green and blue cells alternating throughout the cell structure. The specific configuration illustrated in FIG. 1 is variously referred to as a triangle, or delta configuration, describing the shape that is formed by a group of red, blue and green light-producing cells. One proposed improvement to PDP 10 of FIG. 1 includes thickening the front dielectric layer into a stripe pattern that is positioned toward the discharge gap. Since the discharge is no longer entirely on the surface, a higher efficiency can be achieved using lower discharge voltage.
FIG. 2 illustrates a top view of another conventional PDP structure, PDP 20, and is referred to as a hexagonal or honeycomb grid format PDP. Similar to FIG. 1, in FIG. 2 closed-shape barrier ribs 22 define cells 24 arranged in a delta configuration of color pixels. However in this case the barrier ribs 22, and therefore the cells 24, are hexagonally shaped. The triangle or delta configuration PDP is superior to conventional stripe PDP in higher resolution, lower discharge voltage, higher efficiency, and greater brightness.
Although there are differences between conventional PDP cell structures, the major problem besetting these conventional structures remains low efficiency. This is also referred to as the discharge efficiency, which is the strength of luminescence per unit of injected energy.
Accordingly, there is a need to optimize the efficiency of the PDP by improving the structure of the PDP such that it requires a minimal amount of power for good functionality.